Internal combustion engine construction



2 Sheets-Sheet 1 G. H. BLETTNER INTERNAL COMBUSTION ENGINE CONSTRUCTION Filed Sept. 30, 1955 Jan. 1 l, 1938.

Jan. 11, 1938. G. H. BLETTNER INTERNAL COMBUSTION ENGINE CONSTRUCTION Filed Sept. 30, 1955 2 Sheets-Sheet 2 FE UP 61307"; e 76.31%; ner:

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PATENT INTERNAL COMBUSTION ENGINE CON- STRUCTION George H. Blettner, Chicago, 111., assignor to Renette Company, Chicago, Ill., a corporation of Illinois A 'spiication September 30, 1935, Serial No. 42,776

1 Claim.

The present invention relates to internal combustion engine construction, and has to do more particularly with the provision of reliefs between the pistons and cylinder walls adjacent the exhaust passages of the engines, to accommodate for the growth of the metal of the engine blocks due to undissipated heat to which the portions of the engines between the cylinder walls and the cross passages are subjected.

It has been observed, in internal combustion engines, that adjacent the exhaust ports or exhaust passages of the engine blocks, because of the excess metal there present, repeated starting and stopping of the engines, causes growths of metal adjacent such areas. Furthermore, there being more metal adjacent the head ends of the cylinder blocks, at the exhaust passages, than opposite to the exhaust passages, a tendency to how the cylinder has been observed. The straight cylindrical surfaces of the cylinder have been slightly bent so as to cause wedging action between the pistons and the upper or outer ends of the cylinders whenever the pistons are moved to such ends. Such wedging action has caused the upper lands of the pistons to become crowded to such an extent as to wear the lands excessively and also to tilt the pistons to such an extent as to press the pistons against the cylinder walls opposite the exhaust valves with suf- 30 ficient pressure to cause rapid deterioration of the cylinder walls and wear recesses in the walls opposite the exhaust passages. Such action causes abrasion of the surfaces of the upper ring lands of the pistons and deforms the contour of the opposite sides of the pistons, causing binding, collapse, scuffing and in a short time resulting in oil pumping and rattling of the pistons, thus calling for replacement of the parts. The present invention has to do with the provision of reliefs at the upper or outer ends of the cylinder blocks adjacent the ends thereof to prevent the wedging of the pistons in the cylinders and thus prolong the lives of the engines and pistons.

An object of the present invention is to prolong the life and efiiciency of the pistons and cylinder walls of internal combustion engines by affording additional clearance between the pistons and cylinder walls in areas adjacent the exhaust passages in the cylinder blocks, to accommodate for growth of the metal of the blocks, at such areas, due to undissipated heat to which such areas are subjected.

Another object of the present invention is to provide reliefs on cylinder Walls adjacent the exhaust passages and above the positions occupied by the uppermost piston rings to prevent the cylinder walls, if distorted in this particular area, from contacting the ring lands of the pistons when the pistons reach their uppermost positions during use.

A further object of the present invention is so to construct an internal combustion engine that the distortion and enlargement localized adjacent the exhaust passages in the engine blocks cannot wedge or thrust the pistons against the opposite sides of the cylinder walls while the pistons are operating.

fhe accompanying drawings illustrate an embodiment of the present invention, and the views thereof are as follows:

Figure l is a fragmental axial sectional view through a block of an internal combustion engine showing the cylinder, piston and, in dotted lines, an exhaust passageway and valve for the passageway. The piston is illustrated as having the ring lands relieved to provide space for the growth of a cylinder wall adjacent the exhaust passageway.

Figure 2 is a view similar to Figure 1, showing a recess formed in the cylinder wall adjacent the exhaust passageway for accommodating the growth of metal occurring in this neighborhood.

Figure 3 is a fragmental top plan view of an internal combustion engine block, showing the lands of the pistons relieved to provide spaces adjacent the exhaust passages of the engine.

Figure 4 is a fragmental top plan view of an engine block, showing a recess in the cylinder to provide relief space adjacent the exhaust passage in the block.

Figure 5 is a view similar to Figures 1 and 2, showing how an unrelieved piston is canted or tilted in a cylinder, because of the presence of a growth adjacent the exhaust passage of the engine, and projecting into the cylinder. This view shows, in dotted lines, the truly cylindrical shape of the cylinder as originally fashioned and, at the upper left, in full lines, the recess gouged in the cylinder wall by the tilting of the piston because of the presence of a growth adjacent an exhaust passageway of the block.

The drawings will now be explained.

Figure 1 illustrates a fragmental portion of an engine block casting having a cylinder 1, an exhaust passageway 2, and water cooling compartments 3 surrounding the cylinder for cooling purposes, as Well understood. Between the exhaust passageway 2 and the cylinder 1, the

casting is thickened at 4 by reason of the method of manufacture employed in casting such blocks.

Opposite to the thickened portions 4 of metal,'

the section indicated at 5 is less, so that as expansion and contraction takes place, due to the stopping and starting of the engine, different effects are created at these-points.

Figure 1 illustrates at 6 a growth which has accumulated on the interior of the cylinder wall adjacent the exhaust passageway, and which has become a permanent deforma ion within the truly cylindrical surface of the cylinder I. The dotted lines 1 indicate the cylindrical portion of the cylinder wall.

In order to enable the piston 8 to reach its upper or outward limit of movement adjacent the I head end of the block, the lands 9 and 10 are reduced or flattened to provide a space between the piston and cylinder wall at its upper end to ac- I "ring lands of the. pistons adjacent the exhaust passageway and deforming the contours of the opcommodate the growt 6, and: thus prevent" the wedging or jamming of the piston in the cylinder at the upper limit of its stroke; a V

Figure 3 shows piston 3 relieved as indicated by the line I l, the cylinder'being shown as truly circular. Exhaust valves l2 control exhaust passages in the engine block communicating with the cylinders shown in this figure. The inlet valves !3 are arranged as is common practice and function in a manner well understood.

FigureZ shows the cylinder casting as having a recess or relief space it formed in the wall of the cylinder l adjacent the exhaust passageway 2, the truly cylindrical surface of the cylinder being indicated by the dotted line l5. With the provision of this recess i l, the accumulation of metal or growth at this area would therefore not cause wedging or binding of the piston 8 on reaching its uppermost or outermost limit of travel in service.

Figure 5 shows what happens in an internal combustion engine when metal growth J6 occurs on an area of the cylinder wall adjacent the exhaust passageway 2 and no relief is provided to accommodate for this growth. It willbe observed that the piston I1 has been tilted or canted to the left, and by reason of the travel of-the piston in the cylinder has worn a recess IS in the wall of the cylinder opposite to the exhaust passageway 2, that is, opposite tothe growth l6. In forming the recess i8,a slight ledge 19 remains which lies within the cylindrical contour of the original shape of the cylinder. The dotted. line 20 of this figure shows the original cylindrical contour of the cylinder prior to the formation of the recess i8 therein by the canting or tilting of the piston I? in service.

It is to eliminate the trouble illustrated in Figure 5 that the relief, such as illustrated in Figures 1 and 2, has been provided. Because of the fact that the thicker portion 4 of the engine block casting is between the exhaust passageway 2 and the cylinder, this portion becomes unduly heated in service, and therefore the consequent change of size and shape of the straight cylindrical surface of the cylinder is suflicient to slightly how the cylinder inwardly, thereby causing wedging of the pistons in the upper or outer ends of the cylinders.

It has been observed that this wedging action has, in some instances, been such as to so tightly wedge the upper ends of pistons in the upper ends of cylinders as to result in a tearing apart of the pistons when the direction of travel of the pistons was reversed by the crank shaft.

The obstructional deformation formed by the growt 6 or by a slightly bowed effect of the cylinder due to the heat abovementio-necl is sufficient, unless provision'is made to overcome it, to always press the pistons against the cylinder walls opposite to the exhaust valves with sufficient pressure to cause rapid deterioration of the cylinder walls and as well abrade the surfaces of the upper posite thrust sides of the pistons, causing binding, collapse, scuffing or otherdamage. I

The provision of reliefs on the pistons by flattening the ring lands is caused preferably by tapering off the heads of the pistons along the areas which will be adjacent theexhaust passageways when the pistons are assembled in the engines.

'The growths heretofore mentioned in the neighborhood of the exhaust passageways result from intermittent operations of the engines and eventually become permanently fixed obstructions in the cylinders and are'contacted by the pistons for every revolution of the crank shafts.

It may be stated, by way of example, that in one I internal combustion engine inspected, a growth of as much as .018 inch was observed in 3 inch cylinders, after a sustained operation of the engine while the engine was in a heated condition.

I am aware that many changes may be'made and numerous detailsof construction may be varied through a wide range without departing from the principles of this invention, and I, therefore, do not purpose limiting the patent granted hereon otherwise than is necessitated by the prior art.

The invention is claimed asfollows:

In an internal combustion engine including an engine block casting having therein a cylinder, a

piston reciprocally mounted in said cylinder, and

an exhaust passage, the: upper portion of the block between said passage and adjacent upper cylinder wall being relatively thicker than the portion of said block on the opposite side of said cylinder, localized clearance being provided between said upper cylinder wall portion and that portion of said piston which overrides said wall portion in its travel, whereby any growth of said wall portion is-compensated for and tilting of the piston is prevented.

GEORGE BLETTNER. 

